Add this optional pressure kit to your FermZilla 27L or 55L and turn your FermZilla into a true uni tank. 
Uni tanks are conical fermenters used both for fermentation and for carbonating and serving finished beer. 
This  inexpensive upgrade will enable you to do what the FermZilla was designed for. 

This kit now includes Red and Yellow Carbonation Caps allowing you to differentiate your yellow carbonation cap which has a diptube attached for dispensing/transferring your liquid gold, from the red carbonation cap for gas input.